6.6 CHAPTER 6. CHEMICAL BONDING
- Covalent bondingoccurs between the atoms of non-metals and involves a sharing of
electrons so that the orbitals of the outermost energy levels in the atoms are filled. - Adoubleortriple bondoccurs if there are two or three electron pairs that are shared
between the same two atoms. - Thevalencyis the number of electrons in the outer shell of an atom which are able
to be used to form bonds with other atoms. - Covalent compounds have lower melting and boiling points than ionic compounds.
Covalent compounds are also generally flexible, are generally not soluble in water
and do not conduct electricity. - Anionic bondoccurs between atoms where there is a large difference in electroneg-
ativity. An exchange of electrons takes place and the atoms are held together by the
electrostatic force of attraction between the resulting oppositely-charged ions. - Ionic solids are arranged in acrystal latticestructure.
- Ionic compounds have high melting and boiling points, are brittle in nature, have a
lattice structure and are able to conduct electricity when in solution. - Ametallic bondis the electrostatic attraction between the positively charged nuclei
of metal atoms and the delocalised electrons in the metal. - Metals are able to conduct heat and electricity, they have a metallic lustre (shine), they
are both malleable (flexible) and ductile (stretchable) and they have a high melting
point and density. - We can work out the relative molecular mass for covalent compounds and the for-
mula mass for ionic compounds and metals.
Chapter 6 End of chapter exercises
1. Explain the meaning of each of the following terms
a. ionic bond
b. covalent bond
2. Which ONE of the following best describes the bond formed between
carbon and hydrogen?
a. metallic bond
b. covalent bond
c. ionic bond
3. Which of the following reactions willnottake place? Explain your answer.a. H+H→H 2
b. Ne+Ne→Ne 2
c. Cl+Cl→Cl 2
4. Draw the Lewis structure for each of the following:122 Chemistry: Matter and Materials